Greetings !

> This is correct.  The "new" old generation of 300 series machines
> (i.e. the ones with the "System Interface Board" instead of the "Human
> Interface Board", like the 350, 360, and 370) used a DB9 pin for their
> serial port.  The send and receive lines work fine, but all of the
> handshaking lines are wrong.  The earlier "Human Interface Board" had a
> DB25 with correct wiring (for the 320 and similar machines).
Hm, my 320's Human Interface Board has a female DB9 with nonstandard
pinout.
( DIO-I; has slow HP-IB, HIL and this DB9 serial )

bye
Michael